After reading this article, i realized the possible reason for this delay in international deliveries, so with Tesla having right now 134.000 units registered in the USA until July, some 20.000 Model S & X are expected to be delivered until year end, so we get 154.000 units by the end of Q4.

Add the expected 20-30.000 2017 deliveries from the Model 3, and we have Tesla only 15-25.000 units away from the 200.000 units phase-out process in December, 31st.

At this point, and depending if the difference will be closer to 15k or 25k, Tesla will have two choices to proceed:

A) Goes all out in Q1 to reach the 200k as soon as possible, so it can have the better part of Q1 and the subsequent Q2 to deliver as much Model 3 as possible in the USA, so their customers can profit from the full $7.500 federal tax credit;

B) Manages deliveries so that it only passes the 200k mark in the first days of April, so that it has two full quarters (Q2 and Q3) with the full tax credit.

I don't think even Elon Musk himself knows how this will rollout, many things can go wrong, or not, so the international launch will depend on the production ramp up of the Model 3, if all goes well and they proceed with the A) scenario, then first deliveries abroad should happen in Q3, with volume numbers happening in Q4 2018.

If something delays the ramp up and the B) scenario occurs, then expect first overseas deliveries to happen only in Q4, with volumes increasing during the first months of 2019.

Long story short, the expected "Late 2018" arrival to Europe is ambiguous enough to cover a Q3 2018 launch on the A scenario, or Q4 in the most pessimistic B scenario.